Brake band

ABSTRACT

In a brake band in which a bracket is coupled to an end portion of a curved strap and an apply pin comes into contact with a contact portion of the bracket, thereby generating a fastening force, an abrasion preventing means is provided between the contact portion of the bracket and the apply pin.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a brake band, for example, used in anautomatic transmission of a motor vehicle or the like. Moreparticularly, the present invention relates to a brake band providedwith an abrasion preventing means for preventing an abrasion of abracket.

2. Relevant Background Art

A brake band is constituted by an annular strap broken at one position,a bracket provided in a broken end portion of the strap, and a frictionmember firmly fixed to an inner periphery of the strap, and isstructured such that the strap is wound around a drum by applying aforce on the basis of an apply pin to the bracket in an apply side and abrake force is obtained.

However, the conventional brake band mentioned above has the followingproblem. There is a risk that an abrasion or a breakage is generated ina pin contact portion of the bracket on the basis of a load repeatedlyapplied to an apply pin pressure receiving portion of the apply sidebracket and a malfunction is generated.

In order to solve the problem, for example, in Japanese PatentApplication Laid-open No. H10-169675, the structure is made such that aleading end shape of the apply pin which has been conventionally broughtinto point contact with the apply side bracket is formed in atrapezoidal shape so as to be brought into line contact with thebracket.

However, in the countermeasure mentioned above, since the apply pin isdirectly in contact with the bracket, it is possible to obtain an effectthat a degree of the abrasion is reduced in comparison with the pointcontact, however, a fundamental solution can not be obtained.

Further, as the other countermeasures, there can be considered to changea product specification, for example, reducing a hardness of the applypin itself, making a thickness of the bracket so as to improve astrength of the bracket, changing a material of the bracket so as toincrease a hardness, and the like. However, changing the productspecification may generate a new problem such as an increase of amanufacturing cost or the like.

SUMMARY OF THE INVENTION

Accordingly, an object of the present-invention is to provide a brakeband which employs the conventional structure and raw material as it is,covers a pin pressure receiving portion of a bracket or an apply pin bya cover member, and can reduce an abrasion of a pin contact portion ofthe bracket.

In order to achieve the object mentioned above, in accordance with thepresent invention, there is provided a brake band in which a bracket iscoupled to an end portion of a curved strap and an apply pin comes intocontact with a contact portion of the bracket, thereby generating afastening force,

wherein an abrasion preventing means is provided between the contactportion of the bracket and the apply pin.

In accordance with the present invention, the following effect can beobtained.

It is possible to cover the contact portion of the bracket or the applypin by the cover member without changing the conventional productspecification, and it is possible to reduce the abrasion in the contactportion of the bracket.

Since it is possible to select the material in conformity with ahardness difference from the opposite member, it is possible to easilycorrespond to various use conditions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front elevational view of a brake band to which the presentinvention can be applied;

FIG. 2 is a front elevational view of a main portion of an apply sidebracket and an apply pin and shows a first embodiment in accordance withthe present invention; and

FIG. 3 is a front elevational view of a main portion of an apply sidebracket and an apply pin and shows a second embodiment in accordancewith the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A description will be in detail given below of the present inventionwith reference to the accompanying drawings. In this case, it goeswithout saying that an embodiment described below describes the presentinvention as an exemplification, and does not limit the presentinvention. Further, the same elements in each of the drawings aredenoted by the same reference numerals.

FIG. 1 is a front elevational view of a brake band 10 to which thepresent invention can be applied. The brake band 10 has a strap 1 formedin an approximately annular shape and made of a thin steel plate, anapply side bracket 2 coupled to an end portion 1 a of the strap 1, andan anchor side bracket 3 coupled to the other end portion 1 b of thestrap 1. A friction member 6 is adhered to an inner periphery of thestrap 1 by an adhesive agent or the like. A drum (not shown) is fittedto an inner portion of the strap 1.

An anchor pin 5 is provided in the anchor side bracket 3, and holds theend portion 1 b of the strap 1 in a fixed state. Further, an apply pin 4driven by a drive mechanism (not shown) and having a piston function isbrought into contact with the apply side bracket 2. The apply pin 4presses the apply side bracket 2, thereby deflecting the strap 1,fastening the strap 1 to an outer periphery of a drum (not shown) insuch a manner that the end portions 1 a and 1 b of the strap 1 comeclose to each other, and generating a brake force.

The apply side bracket 2 is provided with a contact portion 2 a formedby folding. The contact portion 2 a is provided with a pressurereceiving surface 2 b facing to the apply pin 4, and a leading endportion 4 a of the apply pin 4 is brought into contact with the pressurereceiving surface 2 b.

Next, a description will be given of each of embodiments in accordancewith the present invention provided with an abrasion preventing means,with reference to FIGS. 2 and 3.

First Embodiment

FIG. 2 is a front elevational view of a main portion of the apply sidebracket 2 and the apply pin 4 and shows a first embodiment in accordancewith the present invention. A cover member 20 covers an approximatelywhole of the contact portion 2 a of the apply side bracket 2.Accordingly, a leading end portion of the apply pin 4 comes into contactthrough the cover member 20 without being directly brought into contactwith the pressure receiving surface 2 b of the contact portion 2 a.

The cover member 20 is formed in a cap shape covering a whole of thecontact portion 2 a, however, does not necessarily cover the whole. Inother words, since the cover member may be formed in a shape covering atleast the pressure receiving portion 2 b, the cover member 20 having amagnitude corresponding to an area of the pressure receiving portion 2 bmay be fixed to the pressure receiving portion 2 b.

Second Embodiment

FIG. 3 is a front elevational view of a main portion of the apply sidebracket 2 and the apply pin 4 and shows a second embodiment inaccordance with the present invention. In the second embodiment, thestructure is made such that the contact portion 2 a of the apply sidebracket 2 is not covered by the cover member, but the leading endportion 4 a of the apply pin 4 is covered by a cover member 21. In thesecond embodiment, a leading end portion of the apply pin 4 comes intocontact through the cover member 21 without being directly brought intocontact with the pressure receiving surface 2 b of the contact portion 2a.

As shown in FIG. 3, the cover member 21 is formed in a cap shapecovering a whole of the leading end portion 4 a of the apply pin 4. Inthe same manner as that of the first embodiment, the cover member may bestructured such as to cover only the portion coming into contact withthe pressure receiving portion 2 b of the apply side bracket in place ofthe whole of the leading end portion 4 a.

In the first and second embodiments mentioned above, a hardness of thecover members 20 and 21 may be equal to a hardness of the apply sidebracket 2 and the apply pin 4 of the leading end portion 4 a, however,in view of preventing the abrasion of the apply side bracket 2, it ispreferable that the cover members 20 and 21 are formed by a materialwhich is harder than the apply pin 4 or the leading end portion 4 a.Further, it is preferable that the cover members 20 and 21 are formed bya material which is softer than the apply side bracket 2.

It is preferable that the cover members 20 and 21 are selected from amaterial which is softer than the apply side bracket 2 and harder thanthe apply pin 4. Further, in each of the embodiments mentioned above,the single cover member 20 or 21 is provided between the apply sidebracket 2 and the apply pin 4, however, a plurality of cover members maybe interposed as occasion demands. In this case, a plurality of covermembers may be made of the same material or have the same hardness,however, it is possible to laminate a plurality of cover members made ofdifferent materials or having different hardness.

In each of the embodiments mentioned above, the apply side bracket 2 andthe anchor side bracket 3 are shown as the different shapes, however,may be formed in the same shape. Further, it goes without saying thatthe present invention can be applied to a brake band having a doublestrap, in place of the brake band having the single strap shown in FIG.1.

This application claims priority from Japanese Patent Application No.2004-321516 filed on Nov. 5, 2004, which is hereby incorporated byreference herein.

1. A brake band in which a bracket is coupled to an end portion of a curved strap and an apply pin comes into contact with a contact portion of said bracket, thereby generating a fastening force, wherein an abrasion preventing means is provided between the contact portion of said bracket and said apply pin.
 2. A brake band according to claim 1, wherein said abrasion preventing means is constituted by a cover member covering the contact portion of said bracket.
 3. A brake band according to claim 2, wherein said cover member is made of a material harder than said apply pin.
 4. A brake band according to claim 1, wherein said abrasion preventing means is constituted by a cover member covering a leading end portion of said apply pin.
 5. A brake band according to claim 4, wherein said cover member is made of a material softer than said bracket.
 6. A brake band according to claim 1, wherein a friction member is provided in an inner periphery of said strap.
 7. A brake band according to claim 2, wherein a friction member is provided in an inner periphery of said strap.
 8. A brake band according to claim 3, wherein a friction member is provided in an inner periphery of said strap.
 9. A brake band according to claim 4, wherein a friction member is provided in an inner periphery of said strap.
 10. A brake band according to claim 5, wherein a friction member is provided in an inner periphery of said strap. 